Due to its advantages such as light weight and thinness, a Liquid Crystal Display (LCD) device has gradually developed as one of the fastest growing flat panel displays. The LCD device displays images using liquid crystal material. The transmittance of the liquid crystals varies with the voltage applied to the liquid crystals, in order for displaying with different gray scales. Further, a color filter layer is placed in the direction of emitting lights for the purpose of displaying images or videos in color. Typically, the LCD device has an input portion including an operation interface, as well as a system portion for processing a signal inputted through the input portion, to display the images or videos by a control signal outputted from the system portion through unidirectional communication.
Recently, a touch panel is integrated with the LCD device to form a touch panel LCD device, so that a user's instruction can be directly inputted through the touch panel disposed on the LCD device, in order for more simple and convenient operations. With the touch panel disposed on the top of the LCD device, when the user touches a displayed icon with his/her finger or a light pen and selects a command to be executed, a touch point (i.e. a touched position) is detected by the touch panel and the LCD device is driven according to the command corresponding to the selected icon, to achieve the specific display. The touch panel can be used without other input means (such as a keyboard or a mouse) and without a keypad for a mobile product, therefore, the LCD device with the touch panel will be more and more widely applied in the display system.
Currently, the touch panel is simply assembled and used with the LCD device. In addition, interferences other than user touch signals need to be eliminated as much as possible during the operation of the touch panel, therefore, a transparent electrode shielding layer is typically disposed between a touch panel electrode layer for detecting the touched position and a common electrode layer of the LCD device, in order to reduce the affection of noise in the LCD device on the touch panel.
FIG. 1 is a schematic view of the structure of an existing touch panel LCD device. As shown in FIG. 1, the existing touch panel LCD device includes a LCD panel 10 and a touch panel 20 independent of and located above the LCD panel 10. The LCD panel 10 includes, from bottom to top, a lower polarizer 11, a lower glass substrate 12, a Thin Film Transistor (TFT) layer 13, a liquid crystal layer 14, a common electrode layer 15, a color filter layer 16, an upper glass substrate 17 and an upper polarizer 18. The touch panel 20 includes, from bottom to top, a transparent shielding layer 21, a glass substrate 22, a touch operating layer 23 and a protective layer 24, with the transparent shielding layer 21 being typically made of an Indium Tin Oxide (ITO) layer. In use, the image displayed by the LCD panel 10 is visible to the user through the touch panel 20, and the user is allowed to perform an information inputting operation by means of the touch panel 20, to implement a man-machine interaction process. However, such a way that the touch panel 20 and the LCD panel 10 are manufactured separately and then assembled together will inevitably increase the thickness of the touch panel LCD device, resulting in a complicated display system and a complex manufacturing process, as well as high costs. Furthermore, although the transparent shielding layer 21 can effectively shield the impact on the touch panel 20 by the electric noise of the LCD panel 10, the provision of the Indium Tin Oxide (ITO) layer not only increases the difficulty of the manufacturing process, but also increases the overall thickness of the whole device, thereby negatively affecting the trend of lightening and thinning of the device.